The second USS Dawn (SP-26) was a motorboat that served in the United States Navy as a repair boat from 1917 to 1918.
Dawn was built in 1914 by Hehre and Aker at Clason Point in The Bronx, New York, as a private motorboat of the same name. The U.S. Navy acquired her from her owner, W. T. Donnelley of Brooklyn, New York, on 19 June 1917 for World War I service as a repair boat, deeming her electric-drive propulsion plant suitable for furnishing electric power for lighting, machine shop work, or repairs. She was commissioned as USS Dawn (SP-26) on 19 June 1917, the day of her acquisition from Donnelley.
Dawn was assigned to the 2nd Naval District. Apparently she did not prove satisfactory in service, for a January 1918 U.S. Navy note commented that the Navy had decided to return her to her owner.
The Navy returned Dawn to Donnelley on 4 April 1918.